President Donald Trump’s moves last week to pull the United States out of the Trans-Pacific Partnership (TPP) and to renegotiate the North American Free Trade Agreement (NAFTA) radically altered the international playing field for farmers in Iowa and around the country.

The new administration’s trade moves were expected, but they still shook up farmers, who rely on exports for a large and growing portion of their incomes. Exports have become even more important in the past few years, as large supplies of both crops and meat have flooded the markets and depressed prices, ag economists said.

With TPP virtually dead and NAFTA being reconsidered, it appears that the era of relying on multi-national trade agreements to reduce tariffs and ease trade restrictions on farm goods is over, agricultural...